Radial Neuropathy

Key Features

• The radial nerve is particularly liable to compression or injury in the axilla (eg, by crutches or by pressure when the arm hangs over the back of a chair)

• The neuropathy may resolve rapidly and spontaneously, or become progressively more disabling

Clinical Findings

• Percussion of the nerve at the site of the lesion may lead to paresthesias in its distal distribution

• Leads to weakness or paralysis of muscles supplied by the nerve, including the triceps, except in cases involving injury near the spiral groove in which the triceps is spared

• Sensory changes may also occur in a small area on the back of the hand between the thumb and index finger

• If injured at or above the elbow, its purely motor posterior interosseous branch, supplying the extensors of the wrist and fingers, may be involved immediately below the elbow, but there is sparing of the extensor carpi radialis longus, so that the wrist can still be extended

• The superficial radial nerve may be compressed by handcuffs or a tight watch strap

Diagnosis

• Electromyography and nerve conduction studies help localize the focal lesion

Treatment

• If acute compression is the cause, then no treatment is needed in most cases

• If repetitive mechanical trauma is responsible, this is avoided by occupational adjustment